WO2023241231A1

WO2023241231A1 - System for recovering argon from single crystal furnace

Info

Publication number: WO2023241231A1
Application number: PCT/CN2023/090732
Authority: WO
Inventors: 马永飞; 程万伟; 张立新; 石望喜; 石焱晶; 贺吉祥
Original assignee: 银川隆基光伏科技有限公司
Priority date: 2022-06-14
Filing date: 2023-04-26
Publication date: 2023-12-21
Also published as: CN217868143U

Abstract

Provided is a system for recovering argon during monocrystalline silicon production. The system comprises: an oxygen supply unit, a dust removal and oil removal filtration unit, a catalytic decarburization unit, a catalytic hydrogenation oxygen removal unit, and a rectification unit. A gas outlet of the dust removal and oil removal filtration unit and an oxygen outlet of the oxygen supply unit are each independently communicated with a gas inlet of the catalytic decarburization unit; a gas outlet of the catalytic decarburization unit is communicated with an inlet for a gas to be treated of the catalytic hydrogenation oxygen removal unit; an outlet of the gas to be treated of the catalytic hydrogenation oxygen removal unit is communicated with an inlet of the rectification unit; a waste argon discharge outlet of the rectification unit is communicated with the gas inlet of the catalytic decarburization unit. The system has a high argon recovery rate, and the purity of argon is high.

Description

A system for recovering argon gas from single crystal furnaces

This application claims priority to the Chinese patent application filed with the China Patent Office on June 14, 2022, with application number 202221487244.3 and titled "A system for recovering argon gas in single crystal furnaces", the entire content of which is incorporated by reference. in this application.

Technical field

The present application relates to the field of gas purification and recovery, specifically, to a system for recovering argon gas in a single crystal furnace.

Background technique

The Czochralski method is the main method for producing single crystal silicon. 70-80% of the world's single crystal silicon is produced by the Czochralski method. The most commonly used Czochralski method for producing single crystal silicon is a decompression crystal pulling process that is both a vacuum process and a flowing atmosphere process. The decompression process is a continuous and constant flow of silicon into the single crystal furnace during the silicon single crystal pulling process. High-purity argon gas is introduced into the furnace, and at the same time, the vacuum pump continuously pumps argon gas out of the furnace to keep the vacuum in the furnace stable at about 20 Torr. This process has the characteristics of both vacuum technology and flowing atmosphere technology. The vacuum pump for the decompression crystal pulling process generally uses a slide valve pump, which is a mechanical vacuum pump that uses oil to maintain a seal. The argon gas carries silicon oxides and impurity volatiles produced due to high temperatures during the single crystal pulling process, and is discharged to the atmosphere through the pumping of the vacuum pump. Through the analysis of the discharged argon gas, the main impurity components are oxygen, nitrogen, carbon monoxide, carbon dioxide, methane and other alkanes, and liquid lubricating oil mist. Recycling this part of argon has great practical significance.

Patent CN102153057A discloses an argon gas recovery and purification method, which specifically uses high-temperature catalytic reaction to remove carbon monoxide and oxygen (in order to ensure that oxygen is removed, hydrogen impurities must be excessively or actively added), normal temperature pressure swing adsorption to remove water and carbon dioxide, and low-temperature temperature swing adsorption to remove water and carbon dioxide. Nitrogen. The disadvantages of this method are low argon recovery rate, complicated equipment control, and the inability to directly remove hydrogen. If hydrogen needs to be removed, other hydrogen removal devices must be added.

Patent US5706674 discloses two argon gas recovery and purification methods. Method 1: remove solid impurities, oil mist, etc. carried in the argon gas through alkaline solution washing at normal temperature, high temperature catalytic removal of oxygen, normal temperature adsorption to remove carbon dioxide and water, and low temperature purification. Heavy components such as hydrocarbons and light components such as nitrogen, hydrogen, and carbon monoxide are distilled away. The cooling capacity required for low-temperature distillation is supplemented by liquid throttling and fresh liquid argon. Method 2: Remove solid impurities, oil mist, etc. carried in the argon gas through alkaline solution washing at normal temperature, catalytically remove oxygen at high temperature, catalytically remove hydrogen and carbon monoxide, adsorb carbon dioxide and water at normal temperature, and adsorb at low temperature. Remove nitrogen and methane. The disadvantages of this method are that it requires the use of alkaline solution, the low-temperature distillation adopts a dual-tower structure coupling control, which is complicated, nitrogen is used for normal temperature adsorption regeneration, and argon is used for low-temperature adsorption regeneration, and the argon recovery rate is low.

There are also technical solutions in the prior art that remove oil and dust from the argon gas recovered from the single crystal furnace, use air as the oxygen source, and react CO and hydrocarbons with oxygen in the air to generate CO ₂ through high-temperature catalysis. During the reaction, the excess oxygen provided in the air is ensured. Finally, after cooling, the excess oxygen reacts with the added hydrogen under the action of a catalyst to generate water. After treatment, the impurity components in the argon gas are water, CO ₂ , H ₂ and N _2. After two The argon gas after the secondary catalytic reaction passes through the normal temperature adsorption unit to adsorb water and CO ₂ , and then enters the low-temperature distillation device to separate hydrogen and nitrogen to obtain argon gas. The disadvantage of this method is that air is added when removing CO and hydrocarbons. Nitrogen is introduced into the system because there is 78% nitrogen in the air. The boiling point of nitrogen is -196°C and the boiling point of argon is -185.9 ℃, the boiling points of the two gases are relatively close. The existing distillation tower cannot completely separate the two gases, and the nitrogen cannot be recycled. Therefore, when processing nitrogen, it is inevitable to discharge a nitrogen-argon mixed gas from the distillation tower, resulting in some Argon gas is discharged and cannot be recovered, and the argon gas recovery rate is low.

Utility model content

The purpose of this utility model is to provide a system for recovering argon gas in the production of single crystal silicon, which can effectively increase the recovery rate of argon gas and obtain high-purity argon gas.

In order to achieve the above purpose, the utility model provides a system for recovering argon gas in the production of monocrystalline silicon. The system includes: an oxygen supply unit, a dust and oil removal filtration unit, a catalytic decarburization unit, a catalytic hydrogenation and oxygen removal unit and Distillation unit;

The gas outlet of the dust removal and oil removal filter unit and the oxygen outlet of the oxygen supply unit are each independently connected to the gas inlet of the catalytic decarburization unit, and the gas outlet of the catalytic decarburization unit is connected to the catalytic hydrogenation unit. The gas to be treated inlet of the deoxygenation unit is connected, the gas to be treated outlet of the catalytic hydrogenation and oxygen removal unit is connected to the inlet of the rectification unit, and the dirty argon gas discharge outlet of the rectification unit is connected to the catalytic decarbonization unit. The gas inlet of the unit is connected.

Optionally, the system also includes a raw material compression unit;

The gas outlet of the dust removal and oil removal filtration unit is connected to the inlet of the raw material compression unit, the outlet of the raw material compression unit is connected to the gas inlet of the catalytic decarburization unit, and the dirty argon gas discharge outlet of the rectification unit is connected. It is connected with the inlet of the raw material compression unit, and the oxygen outlet of the oxygen supply unit is connected with the inlet of the raw material compression unit.

Optionally, the product compression unit includes a compressor and an automatic reflux device; the automatic reflux The device is used to control the inlet main pipe pressure of the compressor to be positive pressure; the number of the compressors is 1-3, and the flow adjustment range of the compressor is 80-100%.

Optionally, the system further includes a product compression unit; the pure liquid argon outlet of the rectification unit is connected with the inlet of the product compression unit.

Optionally, the dust and oil removal filtration unit includes a filter and a fan, the gas outlet of the filter is connected to the inlet of the fan, and the outlet of the fan is connected to the gas inlet of the catalytic decarbonization unit.

Optionally, the catalytic decarbonization unit includes a first heater, a catalytic decarbonization reactor, a first cooler, a first refrigerated dryer and a molecular sieve adsorber;

The outlet of the first heater is connected with the inlet of the catalytic decarburization reactor, the outlet of the catalytic decarburization reactor is connected with the inlet of the first cooler, and the outlet of the first cooler is connected with the inlet of the first cooler. The inlet of the first refrigerated dryer is connected, the outlet of the first refrigerated dryer is connected with the inlet of the molecular sieve adsorber, and the outlet of the molecular sieve adsorber is connected with the catalytic hydrogenation and deoxygenation unit to be treated. The gas inlet is connected.

Optionally, the catalytic hydrogenation and deoxygenation unit includes a second heater, a deaerator, a second cooler, a second freeze dryer and a dehydration adsorber;

The material inlet of the second heater is connected to the gas outlet of the catalytic decarbonization unit, the material outlet of the second heater is connected to the inlet of the deaerator, and the outlet of the deoxidizer is connected to the second The material inlet of the cooler is connected, the material outlet of the second cooler is connected with the material inlet of the second freeze dryer, and the material outlet of the second freeze dryer is connected with the inlet of the dehydration adsorber. , the gas outlet of the dehydration adsorber is connected with the inlet of the rectification unit.

Optionally, the distillation unit includes a cold box and a heat exchanger, a bottom reboiler, a distillation tower, an overhead condenser and a reflux tank arranged in the cold box;

The material inlet to be cooled of the heat exchanger is fluidly connected to the gas outlet to be treated of the catalytic hydrogenation and deoxygenation unit, and the cooling material outlet of the heat exchanger is connected to the heat exchange medium inlet of the column reboiler. , the condensate outlet of the column reboiler is connected to the material inlet of the rectification tower, the top gas outlet of the rectification tower is connected to the inlet of the top condenser, and the top condenser The liquid outlet of the reflux tank is connected with the inlet of the reflux tank, the reflux liquid outlet of the reflux tank is connected with the top reflux liquid inlet of the rectification tower, and the dirty argon gas discharge outlet of the top condenser is connected with the catalytic The gas inlet of the decarburization unit is connected.

Optionally, the hydrogen outlet of the rectification unit and the hydrogen inlet of the catalytic hydrogenation and deoxygenation unit Connected.

Optionally, the oxygen supply unit includes an oxygen generator, and the oxygen outlet of the oxygen generator is connected with the gas inlet of the catalytic decarbonization unit.

Through the above technical solution, the system of the present invention includes an oxygen supply unit and is combined with the recycling of dirty argon gas from the distillation unit, effectively avoiding the nitrogen and argon gas in the subsequent process caused by the introduction of air into the catalytic decarbonization unit. The problem of low argon gas recovery rate is caused by the inability to completely separate the gas and the inability to recycle argon gas.

Other features and advantages of the present invention will be described in detail in the following detailed description.

The above description is only an overview of the technical solutions of the present application. In order to have a clearer understanding of the technical means of the present application, they can be implemented according to the content of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable. , the specific implementation methods of the present application are specifically listed below.

Description of the drawings

In order to more clearly explain the technical solutions in the embodiments of the present application or related technologies, a brief introduction will be made below to the drawings that need to be used in the description of the embodiments or related technologies. Obviously, the drawings in the following description are of the present invention. For some embodiments of the application, those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts.

The accompanying drawings are used to provide a further understanding of the present utility model and constitute a part of the specification. They are used to explain the present utility model together with the following specific embodiments, but do not constitute a limitation of the present utility model. In the attached picture:

Figure 1 is a schematic structural diagram of a specific embodiment of the present utility model.

Explanation of reference signs

1. Dust and oil removal filtration unit 2. Raw material compression unit 3. Catalytic decarburization unit

4. Catalytic hydrogenation and oxygen removal unit 5. Distillation unit 6. Product compression unit

7. Hydrogen supply unit 8. Oxygen supply unit

Specific embodiments

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments These are part of the embodiments of this application, but not all of them. based on The embodiments in this application, and all other embodiments obtained by those of ordinary skill in the art without creative efforts, fall within the scope of protection of this application.

As shown in Figure 1, the utility model provides a system for recovering argon gas in the production of monocrystalline silicon. The system includes: an oxygen supply unit 8, a dust and oil removal filtration unit 1, a catalytic decarburization unit 3, and a catalytic hydrogenation unit. Oxygen removal unit 4 and distillation unit 5; the gas outlet of the dust and oil removal filtration unit 1 and the oxygen outlet of the oxygen supply unit 8 are each independently connected to the gas inlet of the catalytic decarbonization unit 3. The gas outlet of the catalytic decarbonization unit 3 is connected to the gas inlet to be treated of the catalytic hydrogenation and oxygen removal unit 4, and the gas outlet to be treated in the catalytic hydrogenation and oxygen removal unit 4 is connected to the inlet of the rectification unit 5, The waste argon gas discharge outlet of the rectification unit 5 is connected with the gas inlet of the catalytic decarbonization unit 3 .

The system of the utility model includes an oxygen supply unit, and the pure oxygen produced by it is introduced into the catalytic decarbonization unit instead of the air in the traditional process to perform high-temperature catalysis of carbon-containing compounds such as carbon monoxide in the gas to be treated, thus avoiding the problem caused by the introduction of nitrogen in the air. The argon gas cannot be completely separated, causing the problem of low argon gas recovery rate. At the same time, in the system of the present utility model, the dirty argon gas discharged from the distillation unit 5 is recycled back to the catalytic decarbonization unit to further recover the argon gas therein. This system It can effectively improve the recovery rate and purity of argon gas.

As shown in Figure 1, in a specific embodiment of the present invention, the system also includes a raw material compression unit 2, and the gas outlet of the dust and oil removal filter unit 1 is connected with the inlet of the raw material compression unit 2, so The outlet of the raw material compression unit 2 is connected with the gas inlet of the catalytic decarbonization unit 3, the polluted argon gas discharge outlet of the rectification unit 5 is connected with the inlet of the raw material compression unit 2, and the oxygen supply unit 8 is connected with the gas inlet of the catalytic decarbonization unit 3. The oxygen outlet is connected with the inlet of the raw material compression unit 2 . In a preferred embodiment, the raw material compression unit 2 includes a compressor and an automatic reflux device; the automatic reflux device is used to control the inlet main pipe pressure of the compressor to be a positive pressure, and the automatic reflux device can also help The gas volume matching in the pre- and post-adjustment processes refers to adjusting the gas volume to be processed in the catalytic decarburization unit 3 to match. In one embodiment, the raw material compression unit 2 includes a pressurizing device such as a compressor. The compressor is well known to those skilled in the art and may be a centrifugal compressor. The flow adjustment range of the compressor may be 80-100%. , the number of compressors can be selected according to actual needs, for example, it can be 1-4 compressors, preferably 2-4 compressors arranged in parallel, to increase the gas pressure from the dust and oil removal filter unit 1 to 0.6 -0.8MPa for catalytic decarburization unit 3. In this embodiment with more than two compressors in the raw material compression unit 2, two of the compressors are in operation and the remaining compressors are not in operation but are used as backup. use.

As shown in Figure 1, in a specific embodiment of the present invention, the system also includes a product compression unit 6; the pure liquid argon outlet of the rectification unit 5 is connected with the inlet of the product compression unit 6. In a preferred embodiment, the product compression unit 6 includes a product compressor, which is electrically connected to a trace impurity analyzer to detect the argon gas from the rectification unit 5 to ensure that the gas returned to the argon process is qualified. .

According to the present utility model, the dust and oil removal filter unit 1 is used to receive the gas to be processed to remove solid impurities and oil gas in the gas to be processed. The gas to be processed can be the argon-containing tail gas from the single crystal silicon furnace. In one embodiment, the tail gas pipeline of the single crystal silicon furnace is connected to the gas inlet of the dust and oil removal filtration unit 1, and the tail gas pipeline of the single crystal silicon furnace is equipped with an overpressure relief valve to avoid system overpressure. In a preferred embodiment of the present invention, the dust and oil removal filter unit 1 includes a dust filter and a fan. The gas outlet of the dust filter is connected to the inlet of the fan. The outlet of the fan It is connected to the gas inlet of the catalytic decarbonization unit 3, where the fan is used to avoid the problem that the resistance of the tail gas pipeline used to transport the gas to be treated is too large and affects the tail gas emission of the argon process. The fan can be a technology in this field. A well-known blower can be, for example, a Roots blower. The start and stop of the blower is manually started, stopped and switched according to the pressure of the gas to be processed. Preferably, the dust removal filter includes a first dust removal filter and a second dust removal filter. When the first dust removal filter is running, the second dust removal filter is used as a backup. When the second dust removal filter is running, the first dust removal filter is used as a backup. spare. The specific structure and usage of the dust filter are well known to those skilled in the art. In one embodiment, the gas to be treated enters the air inlet of the dust filter through a pipeline, and is filtered through the filter cartridge to block dust in the filter cartridge. On the outer surface, clean gas enters the inside of the filter cartridge and enters the exhaust manifold through the fan. When the surface of the filter cartridge is covered with a certain amount of dust, the electronic pulse backflush dust vibrating device uses argon gas to be instantly blown from the exhaust port of the solenoid valve to form a strong airflow, which will shake off the dust covering the surface of the filter cartridge into the collection box in time. The process automatically backflushes and cleans the filter cartridge by setting the backflush interval and backflush cycle.

According to the present utility model, the catalytic decarbonization unit 3 is used to remove impurities such as CO and hydrocarbons in the gas to be treated. In a specific embodiment of the present invention, the catalytic decarbonization unit 3 includes a first heater, a catalytic decarbonization reactor, a first cooler, a first refrigerated dryer and a molecular sieve adsorber; The outlet of a heater is connected with the inlet of the catalytic decarburization reactor, the outlet of the catalytic decarburization reactor is connected with the inlet of the first cooler, and the outlet of the first cooler is connected with the first The inlet of the refrigerated dryer is connected, the outlet of the first refrigerated dryer is connected with the inlet of the molecular sieve adsorber, and the outlet of the molecular sieve adsorber is connected with the catalytic hydrogenation and oxygen removal unit. The gas to be treated inlet of element 4 is connected. Among them, heaters, catalytic decarburization reactors, regenerators, coolers, freeze dryers and molecular sieve adsorbers are all well known to those skilled in the art. The heater can be, for example, an electric heater. Catalytic decarburization reaction For example, the reactor can be a catalytic reactor, and other types will not be described again here. In the present utility model, the gas to be treated enters the catalytic decarbonization reactor after being heated by the first heater, in which the CO and hydrocarbons in the gas to be treated are burned under the catalysis of the catalyst to become CO ₂ , and then are cooled by the first After the first cold dryer cools down, it enters the molecular sieve adsorber to remove _CO2 and moisture in the gas to be treated, thereby achieving the removal of CO, hydrocarbons and other impurities in the gas to be treated. In a specific embodiment of the present invention, the catalytic decarburization unit 3 also includes a first regenerator and a second regenerator, wherein the inlet of the first regenerator is connected to the dust and oil removal unit. The gas outlet of the filter unit 1 is connected, the outlet of the first regenerator is connected with the inlet of the first heater, the outlet of the first heater is connected with the inlet of the catalytic decarbonization reactor, and the The outlet of the catalytic decarburization reactor is connected to the inlet of the second regenerator, the outlet of the second regenerator is connected to the inlet of the first cooler, and the outlet of the first cooler is connected to the inlet of the first cooler. The inlet of the first refrigerated dryer is connected, the outlet of the first refrigerated dryer is connected with the inlet of the molecular sieve adsorber, and the outlet of the molecular sieve adsorber is connected with the catalytic hydrogenation and oxygen removal unit 4 to be treated. The gas inlet is connected. Regenerators are well known to those skilled in the art, and their specific structures and methods of use will not be described in detail here.

According to the present utility model, the methods for switching and regenerating the molecular sieve adsorber are well known to those skilled in the art. In a specific embodiment, the regeneration of the decarburized molecular sieve used in the catalytic decarburization reactor includes pressure relief, heating, There are 6 steps: first cold blow, second cold blow, pressure equalization and collinearity. Among them, the molecular sieve adsorber includes a first molecular sieve adsorber and a second molecular sieve adsorber. When one of the molecular sieve adsorbents is in the adsorption state, the other molecular sieve adsorbent is in the regeneration state, and is automatically controlled by the program to switch every 10-14 hours. In a specific implementation, the first molecular sieve adsorber is in the adsorption working state, and the second molecular sieve adsorber is in the regeneration state. At the preset switching moment, all valves at the inlet and outlet of the second molecular sieve adsorber are automatically closed and opened evenly. The pressure valve increases the pressure of the second molecular sieve adsorber. When the pressure of the second molecular sieve adsorber is consistent with the pressure of the first molecular sieve adsorber, close the pressure equalizing valve, and then open the forward flow inlet and outlet valve to switch the second molecular sieve adsorber to the adsorption working state. After the first molecular sieve adsorber and the second molecular sieve adsorber work in parallel for a period of time, the first molecular sieve adsorber switches to a regeneration state. At this time, the forward flow inlet and outlet valve of the first molecular sieve adsorber is closed and the pressure relief valve is opened. After the pressure relief is completed, the reverse flow inlet and outlet valve is opened and the vent valve is closed. In the first half of the catalyst regeneration, the heater is started to heat the regeneration gas to above 170°C. In the second half, the heating is stopped to blow the cold adsorber. In the last stage, the cold box exhaust gas is switched to flow into the cold box. Lower the adsorber temperature step by step. The regeneration gas is provided by the air valve or waste nitrogen throttling, and the pressure and flow rate of the regeneration gas are automatically adjusted.

According to the present utility model, the catalytic hydrogenation and oxygen removal unit 4 is used to perform a catalytic reaction to remove oxygen from the gas to be treated. In a specific embodiment of the present invention, the catalytic hydrogenation and oxygen removal unit 4 includes a second heater, a deaerator, a second cooler, a second freeze dryer and a dehydration adsorber; the second The material inlet of the heater is connected with the gas outlet of the catalytic decarbonization unit 3, the material outlet of the second heater is connected with the inlet of the deaerator, and the outlet of the deoxidizer is connected with the second cooler. The material inlet is connected, the material outlet of the second cooler is connected with the material inlet of the second refrigerated dryer, the material outlet of the second refrigerated dryer is connected with the inlet of the dehydration adsorber, and the material outlet of the second cooler is connected with the material inlet of the second freeze dryer. The gas outlet of the dehydration adsorber is connected with the inlet of the rectification unit 5 . In the present utility model, the second heater, deaerator, second cooler, second freeze dryer and dehydration absorber are well known to those skilled in the art. The deaerator can be, for example, a deoxidation furnace. Other types are This will not be described again. In one embodiment, the hydrogen used in the catalytic hydrogenation and oxygen removal unit 4 comes from the hydrogen supply unit 7 , and the hydrogen outlet of the hydrogen supply unit 7 is connected with the gas inlet to be treated of the catalytic hydrogenation and oxygen removal unit 4 . In a specific embodiment of the present invention, the hydrogen supply unit 7 includes an electrolytic hydrogen production device.

In the present utility model, the distillation unit 5 is used to purify argon gas. In a specific embodiment of the present invention, the rectification unit 5 includes a cold box and a heat exchanger, a column reboiler, a distillation tower, an overhead condenser and a reflux unit arranged in the cold box. Can. Among them, the cold box is provided with pearlescent sand insulation to maintain a low-temperature working environment; the material inlet to be cooled of the heat exchanger is in fluid communication with the gas outlet to be treated of the catalytic hydrogenation and deoxygenation unit 4, and the heat exchanger The cooling material outlet of the reactor is connected to the heat exchange medium inlet of the column reboiler, the condensate outlet of the column reboiler is connected to the material inlet of the rectification tower, and the top of the rectification tower The gas outlet is connected to the inlet of the top condenser, the liquid outlet of the top condenser is connected to the inlet of the reflux tank, and the reflux liquid outlet of the reflux tank is connected to the top reflux liquid of the rectification tower. The inlet is connected, and the waste argon gas discharge outlet of the tower top condenser is connected with the gas inlet of the catalytic decarbonization unit 3 . In the present utility model, the gas to be treated from the catalytic hydrogenation and deoxygenation unit 4 enters the heat exchanger and exchanges heat with the refluxing low-temperature gas, and then is cooled to about -166°C, and then is mixed with the liquid argon in the tower still reboiler. After further heat exchange, it is cooled to about -171°C to condense most of the argon gas into liquid, and a small part of the non-condensable hydrogen-containing gas is returned to the heat exchanger for reheating, venting or recycling. The liquid argon at the bottom of the tower is throttled by the throttle valve and enters the upper part of the distillation tower for rectification. The pressure of the distillation tower is about 0.25MPa. The liquid and the rising steam continuously transfer heat and mass, and are obtained in the still of the distillation tower. Qualified liquid argon. The rising steam comes from the evaporated liquid argon in the tower kettle reboiler. The greater the process argon flow rate, the greater the evaporation load, and the higher the argon tower resistance. In one embodiment, the overhead condenser includes a main condenser and an auxiliary condenser. The steam at the top of the distillation tower enters the main condenser and the auxiliary condenser and is cooled into liquid and then partially refluxes into the tower through the reflux tank to continue rectification. , the non-condensed exhaust gas is vented. The cold source of the main condenser comes from the liquid argon in the tower kettle, which is throttled to about 50kPa by the upper tower regulating valve and vaporized and reheated to become a product. The cold source of the auxiliary condenser is liquid air.

In a specific embodiment of the present invention, the hydrogen outlet of the rectification unit 5 is connected with the hydrogen inlet of the catalytic hydrogenation and deoxygenation unit 4 to achieve further recycling of hydrogen in the system.

In a specific embodiment of the present invention, the oxygen supply unit 8 includes an oxygen generator, and the oxygen outlet of the oxygen generator is connected with the gas inlet of the catalytic decarbonization unit 3 . The structure and usage of an oxygen generator are well known to those skilled in the art and will not be described in detail here.

The present utility model will be further described below through examples, but the present utility model is not subject to any limitation thereby.

Example 1

The tail gas to be treated from the single crystal furnace will be introduced into the dust and oil removal filtration unit 1 for oil and dust removal to remove oil mist and solid particles in the argon gas; the treated tail gas will be sent to the compressor of the raw material compression unit 2 to remove oil and dust. The pressure of the tail gas to be treated is increased to 0.7MPa; the pressure-raised tail gas to be treated is heated by the first regenerator and the first heater in the catalytic decarbonization unit 3 and then sent to the catalytic decarbonization reactor. The reaction causes impurities such as CO and hydrocarbons to react with the pure oxygen prepared by the oxygen generator in the catalytic hydrogenation and deoxygenation unit 4 to generate water and carbon dioxide. An excess of pure oxygen is ensured during the catalytic reaction, and the obtained tail gas to be treated is reheated for the second time After being cooled down by the first cooler and the first cold dryer, it enters the molecular sieve adsorber to remove CO ₂ and water; the decarbonized tail gas from the catalytic decarbonization unit 3 is passed through the second catalytic hydrogenation and deoxygenation unit 4 After the heater is heated and raised, the excess oxygen in the decarburized tail gas reacts with the hydrogen from the hydrogen supply unit 7 to generate water under the action of the catalyst in the deoxidizer, and ensures that the excess hydrogen is reacted. The gas to be treated with the oxygen removed passes through the second cooler. , the second refrigerated dryer and the dehydration adsorber remove the moisture; send the tail gas to be treated from the catalytic hydrogenation and deoxygenation unit 4 into the heat exchanger of the distillation unit 5 to exchange heat with the returning low-temperature gas and then cool it. to -166°C, and then further heat exchanged with the liquid argon in the tower kettle reboiler and then cooled to -171°C to condense most of the argon gas into liquid. The liquid argon at the bottom of the tower enters the distillation tower through the throttle valve. The upper part of the column is distilled to separate hydrogen and argon. The pressure of the distillation tower is 0.25MPa. The liquid With continuous heat and mass transfer with the rising steam, qualified liquid argon is obtained in the still of the distillation tower. After the steam at the top of the distillation tower enters the top condenser and the reflux tank and becomes liquid, part of the liquid is refluxed into the distillation tower through the reflux tank to continue distillation. The non-condensed hydrogen is vented and the dirty argon gas is recycled back to the raw material compression unit 2 to continue. Recycling: The argon gas from the rectification unit 5 is sent to the product compression unit 6 for processing and the pressure is raised to about 0.5MPa and returned to the argon supply process. The utility model system can increase the recovery rate of argon gas to 98%.

Comparative example 1

The same method as in Example 1 is used to process the exhaust gas to be treated from the single crystal furnace. The only difference is that air is used as the oxygen source in the catalytic decarbonization unit 3 to remove impurities such as CO and hydrocarbons in the exhaust gas to be treated. After the distillation unit 5 separates part of the hydrogen and nitrogen, the obtained nitrogen-argon mixed gas is directly discharged, and the argon gas therein cannot be further recycled. The system's argon recovery rate is only 92%.

It can be seen from the above that the system of the present invention includes an oxygen supply unit, which uses pure oxygen as the oxygen source for decarbonization and recycling of polluted argon gas, thus avoiding the need for air as the oxygen source in the traditional process of Comparative Example 1. The introduction of nitrogen into the system during decarbonization treatment resulted in the inability to completely separate the two gases due to the close boiling points of nitrogen and argon. As a result, the distillation tower inevitably discharged nitrogen-argon mixed gas when separating argon and nitrogen, making it impossible to proceed further. Recycling and utilizing the argon gas in the nitrogen-argon mixed gas results in the emission of part of the argon gas, resulting in a low argon gas recovery rate. The system of the present invention can effectively improve the argon gas recovery rate.

The preferred embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the specific details in the above-mentioned embodiments. Within the scope of the technical concept of the present utility model, many technical solutions of the present utility model can be carried out. These simple modifications all belong to the protection scope of the present utility model.

In addition, it should be noted that each of the specific technical features described in the above-mentioned specific embodiments can be combined in any suitable manner without conflict. In order to avoid unnecessary repetition, the present utility model combines various possible The combination method will not be further explained.

In addition, any combination of various embodiments of the present invention can also be carried out. As long as they do not violate the idea of the present utility model, they should also be regarded as the disclosed content of the present utility model.

The device embodiments described above are only illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in One location, or it can be distributed across multiple network units. Some or all of the modules can be selected according to actual needs to implement this embodiment. purpose of the program. Persons of ordinary skill in the art can understand and implement the method without any creative effort.

Reference herein to "one embodiment," "an embodiment," or "one or more embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. In addition, please note that the examples of the word "in one embodiment" here do not necessarily all refer to the same embodiment.

In the instructions provided here, a number of specific details are described. However, it is understood that embodiments of the present application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent substitutions are made to some of the technical features; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions in the embodiments of the present application.

Claims

A system for recovering argon gas in the production of monocrystalline silicon, characterized in that the system includes: an oxygen generation unit (8), a dust and oil removal filtration unit (1), a catalytic decarburization unit (3), and a catalytic hydrogenation unit. Deaeration unit (4) and distillation unit (5);

The gas outlet of the dust and oil removal filter unit (1) and the oxygen outlet of the oxygen supply unit (8) are each independently connected to the gas inlet of the catalytic decarburization unit (3). The catalytic decarburization unit The gas outlet of (3) is connected to the gas inlet to be treated of the catalytic hydrogenation and oxygen removal unit (4), and the gas outlet to be treated of the catalytic hydrogenation and oxygen removal unit (4) is connected to the rectification unit (5). The inlet of the rectification unit (5) is connected with the gas inlet of the catalytic decarbonization unit (3).
The system according to claim 1, characterized in that the system further comprises a raw material compression unit (2);

The gas outlet of the dust and oil removal filtration unit (1) is connected to the inlet of the raw material compression unit (2), and the outlet of the raw material compression unit (2) is connected to the gas inlet of the catalytic decarburization unit (3). , the dirty argon gas discharge outlet of the rectification unit (5) is connected with the inlet of the raw material compression unit (2), and the oxygen outlet of the oxygen supply unit (8) is connected with the inlet of the raw material compression unit (2) Connected.
The system according to claim 2, characterized in that the raw material compression unit (2) includes a compressor and an automatic reflux device; the automatic reflux device is used to control the inlet main pipe pressure of the compressor to be positive pressure; The number of the compressors is 1-4, and the flow adjustment range of the compressors is 80-100%.
The system according to claim 1, characterized in that the system further includes a product compression unit (6); the pure liquid argon outlet of the rectification unit (5) is connected with the inlet of the product compression unit (6).
The system according to claim 1, characterized in that the dust and oil removal filter unit (1) includes a dust filter and a fan, the gas outlet of the dust filter is connected to the inlet of the fan, and the fan The outlet is connected with the gas inlet of the catalytic decarburization unit (3).
The system according to claim 1, characterized in that the catalytic decarbonization unit (3) includes a first heater, a catalytic decarbonization reactor, a first cooler, a first refrigerated dryer and a molecular sieve adsorber;

The outlet of the first heater is connected with the inlet of the catalytic decarburization reactor, the outlet of the catalytic decarburization reactor is connected with the inlet of the first cooler, and the outlet of the first cooler is connected with the inlet of the first cooler. The inlet of the first refrigerated dryer is connected, the outlet of the first refrigerated dryer is connected with the inlet of the molecular sieve adsorber, and the outlet of the molecular sieve adsorber is connected with the catalytic hydrogenation and deoxygenation unit (4) The gas inlet to be treated is connected.
The system according to claim 1, characterized in that the catalytic hydrogenation and oxygen removal unit (4) includes a second heater, a deaerator, a second cooler, a second freeze dryer and a dehydration adsorber;

The material inlet of the second heater is connected to the gas outlet of the catalytic decarbonization unit (3), the material outlet of the second heater is connected to the inlet of the deoxidizer, and the outlet of the deoxidizer is connected to the gas outlet of the deoxidizer. The material inlet of the second cooler is connected, the material outlet of the second cooler is connected with the material inlet of the second refrigerated dryer, and the material outlet of the second refrigerated dryer is connected with the dehydration adsorber. The inlet of the dehydration adsorber is connected with the gas outlet of the dehydration adsorber and the inlet of the rectification unit (5).
The system according to claim 1, characterized in that the rectification unit (5) includes a cold box and a heat exchanger, a column reboiler, a distillation tower and a tower top condensation device arranged in the cold box. container and reflux tank;

The material inlet to be cooled of the heat exchanger is in fluid communication with the gas outlet to be treated of the catalytic hydrogenation and deoxygenation unit (4), and the cooling material outlet of the heat exchanger is in heat exchange with the column reboiler. The medium inlet is connected, the condensate outlet of the tower still reboiler is connected with the material inlet of the rectification tower, the top gas outlet of the rectification tower is connected with the inlet of the top condenser, and the tower The liquid outlet of the top condenser is connected with the inlet of the reflux tank, the reflux liquid outlet of the reflux tank is connected with the top reflux liquid inlet of the rectification tower, and the dirty argon gas discharge outlet of the top condenser is connected with the inlet of the reflux tank. The gas inlet of the catalytic decarburization unit (3) is connected.
The system according to claim 1, characterized in that the hydrogen in the distillation unit (5) The gas outlet is connected with the hydrogen inlet of the catalytic hydrogenation and deoxygenation unit (4).
The system according to claim 1, characterized in that the oxygen supply unit (8) includes an oxygen generator, and the oxygen outlet of the oxygen generator is connected with the gas inlet of the catalytic decarbonization unit (3).